The LLVM Project recently released a new version of their compiler, optimizer and code generators. LLVM includes a drop-in GCC-compatible C/C++ and ObjC compiler, mature optimization technology (including cross file/whole program optimization), and a highly optimizing code generator. For people who enjoy hacking on compilers and runtimes, LLVM provides libraries for implementing custom optimizers and code generators including JIT compiler support. This release is the first to provide beta GCC 4.2 compatibility as well as the new "clang" C/ObjC front-end, which provides capabilities to build source-to-source translators and many other tools.

yeah... academic groups produce new chip ideas now and then. See Sun's Niagra, for example. It was developed out by Sun, but the initial version was done by a Professor and his grad students.

Intel's Terrascale was also made by a small group. Look up Cavium's OCTEON as well.

Smaller experimental chips are more likely to need compiler support to test out their design ideas before going into mass production. If the researcher has a backend IR with some non-chip-specific optimizations, she has a great basis to work with for designing a specialized processor.

I think the cost of writing compiler backends would be insignificant compared to the cost of developing new chips. Do you have reasons to believe the contrary?

It depends on what you're trying to do.

If you're trying to create a clockless chip, I'm sure the chip development is far more expensive than the compiler development.

But look at the Itanium. It's a chip with a lot of theoretical performance. Getting that improvement requires vastly more work from compilers than on other architectures. No one has really managed to make the chip shine yet.